From 1149af626578fbaf16c5ddf7cd06ee5ba57bff99 Mon Sep 17 00:00:00 2001
From: Filip Skokan <panva.ip@gmail.com>
Date: Fri, 20 Nov 2020 12:59:13 +0100
Subject: [PATCH] crypto: add keyObject.asymmetricKeyDetails for asymmetric
 keys
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Content-Transfer-Encoding: 8bit

This API exposes key details. It is conceptually different from the
previously discussed keyObject.fields property since it does not give
access to information that could compromise the security of the key, and
the obtained information cannot be used to uniquely identify a key.

The intended purpose is to determine "security properties" of keys, e.g.
to generate a new key pair with the same parameters, or to decide
whether a key is secure enough.

closes #30045

PR-URL: https://github.com/nodejs/node/pull/36188
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: Rich Trott <rtrott@gmail.com>
---
 doc/api/crypto.md                        | 19 ++++++
 lib/internal/crypto/keys.js              | 29 +++++++++
 lib/internal/crypto/util.js              | 13 ++++
 test/parallel/test-crypto-key-objects.js |  1 +
 test/parallel/test-crypto-keygen.js      | 81 ++++++++++++++++++++++--
 5 files changed, 139 insertions(+), 4 deletions(-)

diff --git a/doc/api/crypto.md b/doc/api/crypto.md
index 18f52eb4f8ec5d..b56420bce9a1c7 100644
--- a/doc/api/crypto.md
+++ b/doc/api/crypto.md
@@ -1284,6 +1284,25 @@ passing keys as strings or `Buffer`s due to improved security features.
 The receiver obtains a cloned `KeyObject`, and the `KeyObject` does not need to
 be listed in the `transferList` argument.
 
+### `keyObject.asymmetricKeyDetails`
+<!-- YAML
+added: REPLACEME
+-->
+
+* {Object}
+  * `modulusLength`: {number} Key size in bits (RSA, DSA).
+  * `publicExponent`: {bigint} Public exponent (RSA).
+  * `divisorLength`: {number} Size of `q` in bits (DSA).
+  * `namedCurve`: {string} Name of the curve (EC).
+
+This property exists only on asymmetric keys. Depending on the type of the key,
+this object contains information about the key. None of the information obtained
+through this property can be used to uniquely identify a key or to compromise
+the security of the key.
+
+RSA-PSS parameters, DH, or any future key type details might be exposed via this
+API using additional attributes.
+
 ### `keyObject.asymmetricKeyType`
 <!-- YAML
 added: v11.6.0
diff --git a/lib/internal/crypto/keys.js b/lib/internal/crypto/keys.js
index f54393a5e3b4bd..9d6f86d32b0b78 100644
--- a/lib/internal/crypto/keys.js
+++ b/lib/internal/crypto/keys.js
@@ -5,6 +5,7 @@ const {
   ObjectDefineProperty,
   ObjectSetPrototypeOf,
   Symbol,
+  Uint8Array,
 } = primordials;
 
 const {
@@ -36,6 +37,7 @@ const {
   kHandle,
   kKeyObject,
   getArrayBufferOrView,
+  bigIntArrayToUnsignedBigInt,
 } = require('internal/crypto/util');
 
 const {
@@ -128,12 +130,39 @@ const [
   }
 
   const kAsymmetricKeyType = Symbol('kAsymmetricKeyType');
+  const kAsymmetricKeyDetails = Symbol('kAsymmetricKeyDetails');
+
+  function normalizeKeyDetails(details = {}) {
+    if (details.publicExponent !== undefined) {
+      return {
+        ...details,
+        publicExponent:
+          bigIntArrayToUnsignedBigInt(new Uint8Array(details.publicExponent))
+      };
+    }
+    return details;
+  }
 
   class AsymmetricKeyObject extends KeyObject {
     get asymmetricKeyType() {
       return this[kAsymmetricKeyType] ||
              (this[kAsymmetricKeyType] = this[kHandle].getAsymmetricKeyType());
     }
+
+    get asymmetricKeyDetails() {
+      switch (this.asymmetricKeyType) {
+        case 'rsa':
+        case 'rsa-pss':
+        case 'dsa':
+        case 'ec':
+          return this[kAsymmetricKeyDetails] ||
+             (this[kAsymmetricKeyDetails] = normalizeKeyDetails(
+               this[kHandle].keyDetail({})
+             ));
+        default:
+          return {};
+      }
+    }
   }
 
   class PublicKeyObject extends AsymmetricKeyObject {
diff --git a/lib/internal/crypto/util.js b/lib/internal/crypto/util.js
index 67cb9841928a2d..9d2fee2b2dd57a 100644
--- a/lib/internal/crypto/util.js
+++ b/lib/internal/crypto/util.js
@@ -3,6 +3,7 @@
 const {
   ArrayPrototypeIncludes,
   ArrayPrototypePush,
+  BigInt,
   FunctionPrototypeBind,
   Number,
   Promise,
@@ -308,6 +309,17 @@ function bigIntArrayToUnsignedInt(input) {
   return result;
 }
 
+function bigIntArrayToUnsignedBigInt(input) {
+  let result = 0n;
+
+  for (let n = 0; n < input.length; ++n) {
+    const n_reversed = input.length - n - 1;
+    result |= BigInt(input[n]) << 8n * BigInt(n_reversed);
+  }
+
+  return result;
+}
+
 function getStringOption(options, key) {
   let value;
   if (options && (value = options[key]) != null)
@@ -413,6 +425,7 @@ module.exports = {
   jobPromise,
   lazyRequire,
   validateMaxBufferLength,
+  bigIntArrayToUnsignedBigInt,
   bigIntArrayToUnsignedInt,
   getStringOption,
   getUsagesUnion,
diff --git a/test/parallel/test-crypto-key-objects.js b/test/parallel/test-crypto-key-objects.js
index fdb63afa7659f3..34c2cef4c7677c 100644
--- a/test/parallel/test-crypto-key-objects.js
+++ b/test/parallel/test-crypto-key-objects.js
@@ -70,6 +70,7 @@ const privateDsa = fixtures.readKey('dsa_private_encrypted_1025.pem',
   assert.strictEqual(key.type, 'secret');
   assert.strictEqual(key.symmetricKeySize, 32);
   assert.strictEqual(key.asymmetricKeyType, undefined);
+  assert.strictEqual(key.asymmetricKeyDetails, undefined);
 
   const exportedKey = key.export();
   assert(keybuf.equals(exportedKey));
diff --git a/test/parallel/test-crypto-keygen.js b/test/parallel/test-crypto-keygen.js
index f59a26a422f96d..c27d5fe166220e 100644
--- a/test/parallel/test-crypto-keygen.js
+++ b/test/parallel/test-crypto-keygen.js
@@ -114,6 +114,31 @@ const sec1EncExp = (cipher) => getRegExpForPEM('EC PRIVATE KEY', cipher);
   testSignVerify(publicKey, privateKey);
 }
 
+{
+  // Test sync key generation with key objects with a non-standard
+  // publicExpononent
+  const { publicKey, privateKey } = generateKeyPairSync('rsa', {
+    publicExponent: 3,
+    modulusLength: 512
+  });
+
+  assert.strictEqual(typeof publicKey, 'object');
+  assert.strictEqual(publicKey.type, 'public');
+  assert.strictEqual(publicKey.asymmetricKeyType, 'rsa');
+  assert.deepStrictEqual(publicKey.asymmetricKeyDetails, {
+    modulusLength: 512,
+    publicExponent: 3n
+  });
+
+  assert.strictEqual(typeof privateKey, 'object');
+  assert.strictEqual(privateKey.type, 'private');
+  assert.strictEqual(privateKey.asymmetricKeyType, 'rsa');
+  assert.deepStrictEqual(privateKey.asymmetricKeyDetails, {
+    modulusLength: 512,
+    publicExponent: 3n
+  });
+}
+
 {
   // Test sync key generation with key objects.
   const { publicKey, privateKey } = generateKeyPairSync('rsa', {
@@ -123,10 +148,18 @@ const sec1EncExp = (cipher) => getRegExpForPEM('EC PRIVATE KEY', cipher);
   assert.strictEqual(typeof publicKey, 'object');
   assert.strictEqual(publicKey.type, 'public');
   assert.strictEqual(publicKey.asymmetricKeyType, 'rsa');
+  assert.deepStrictEqual(publicKey.asymmetricKeyDetails, {
+    modulusLength: 512,
+    publicExponent: 65537n
+  });
 
   assert.strictEqual(typeof privateKey, 'object');
   assert.strictEqual(privateKey.type, 'private');
   assert.strictEqual(privateKey.asymmetricKeyType, 'rsa');
+  assert.deepStrictEqual(privateKey.asymmetricKeyDetails, {
+    modulusLength: 512,
+    publicExponent: 65537n
+  });
 }
 
 {
@@ -268,9 +301,17 @@ const sec1EncExp = (cipher) => getRegExpForPEM('EC PRIVATE KEY', cipher);
   }, common.mustSucceed((publicKey, privateKey) => {
     assert.strictEqual(publicKey.type, 'public');
     assert.strictEqual(publicKey.asymmetricKeyType, 'rsa-pss');
+    assert.deepStrictEqual(publicKey.asymmetricKeyDetails, {
+      modulusLength: 512,
+      publicExponent: 65537n
+    });
 
     assert.strictEqual(privateKey.type, 'private');
     assert.strictEqual(privateKey.asymmetricKeyType, 'rsa-pss');
+    assert.deepStrictEqual(privateKey.asymmetricKeyDetails, {
+      modulusLength: 512,
+      publicExponent: 65537n
+    });
 
     // Unlike RSA, RSA-PSS does not allow encryption.
     assert.throws(() => {
@@ -342,6 +383,28 @@ const sec1EncExp = (cipher) => getRegExpForPEM('EC PRIVATE KEY', cipher);
   }));
 }
 
+{
+  // Test async DSA key object generation.
+  generateKeyPair('dsa', {
+    modulusLength: 512,
+    divisorLength: 256
+  }, common.mustSucceed((publicKey, privateKey) => {
+    assert.strictEqual(publicKey.type, 'public');
+    assert.strictEqual(publicKey.asymmetricKeyType, 'dsa');
+    assert.deepStrictEqual(publicKey.asymmetricKeyDetails, {
+      modulusLength: 512,
+      divisorLength: 256
+    });
+
+    assert.strictEqual(privateKey.type, 'private');
+    assert.strictEqual(privateKey.asymmetricKeyType, 'dsa');
+    assert.deepStrictEqual(privateKey.asymmetricKeyDetails, {
+      modulusLength: 512,
+      divisorLength: 256
+    });
+  }));
+}
+
 {
   // Test async elliptic curve key generation, e.g. for ECDSA, with a SEC1
   // private key.
@@ -925,16 +988,24 @@ const sec1EncExp = (cipher) => getRegExpForPEM('EC PRIVATE KEY', cipher);
   // It should recognize both NIST and standard curve names.
   generateKeyPair('ec', {
     namedCurve: 'P-256',
-    publicKeyEncoding: { type: 'spki', format: 'pem' },
-    privateKeyEncoding: { type: 'pkcs8', format: 'pem' }
   }, common.mustSucceed((publicKey, privateKey) => {
+    assert.deepStrictEqual(publicKey.asymmetricKeyDetails, {
+      namedCurve: 'prime256v1'
+    });
+    assert.deepStrictEqual(privateKey.asymmetricKeyDetails, {
+      namedCurve: 'prime256v1'
+    });
   }));
 
   generateKeyPair('ec', {
     namedCurve: 'secp256k1',
-    publicKeyEncoding: { type: 'spki', format: 'pem' },
-    privateKeyEncoding: { type: 'pkcs8', format: 'pem' }
   }, common.mustSucceed((publicKey, privateKey) => {
+    assert.deepStrictEqual(publicKey.asymmetricKeyDetails, {
+      namedCurve: 'secp256k1'
+    });
+    assert.deepStrictEqual(privateKey.asymmetricKeyDetails, {
+      namedCurve: 'secp256k1'
+    });
   }));
 }
 
@@ -945,9 +1016,11 @@ const sec1EncExp = (cipher) => getRegExpForPEM('EC PRIVATE KEY', cipher);
       generateKeyPair(keyType, common.mustSucceed((publicKey, privateKey) => {
         assert.strictEqual(publicKey.type, 'public');
         assert.strictEqual(publicKey.asymmetricKeyType, keyType);
+        assert.deepStrictEqual(publicKey.asymmetricKeyDetails, {});
 
         assert.strictEqual(privateKey.type, 'private');
         assert.strictEqual(privateKey.asymmetricKeyType, keyType);
+        assert.deepStrictEqual(privateKey.asymmetricKeyDetails, {});
       }));
     });
   }